The present invention relates generally to pipe crawlers, and more specifically to a sewer pipe crawler for traveling up a sewer pipe against the flow of sewage.
Pipe crawlers for traveling inside pipes are used for such purposes as inspection and cleaning.
Typical prior art mechanisms for moving pipe crawlers through a pipe include wheels and cable driven systems.
Many prior art pipe crawlers use inchworm like mechanisms to move along the inside of a pipe.
Examples of such inchworm-like mechanisms are described in U.S. Pat. Nos. 5,018,451, 5,121,694 and 5,309,844 to Zollinger and Zollinger et al.; U.S. Pat. No. 5,018,451 to Hapstack; and, U.S. Pat. No. 6,427,602 to Holvis et al.
U.S. Pat. Nos. 5,018,451, 5,121,694 and 5,309,844 to Zollinger and Zollinger et al., and U.S. Pat. No. 5,018,451 to Hapstack describe using pneumatics to push, or extend, legs attached to one end of a pipe crawler radially outward against the inside wall of a pipe, then pneumatically extending the body of the pipe crawler to move an assembly of similar legs forward, pneumatically extending those forward legs radially outward against the inside of the pipe, then pneumatically pulling the rear leg assembly forward to advance the pipe crawler, and repeating those movements as necessary to move forward inside the pipe.
U.S. Pat. No. 6,427,602 to Holvis et al. similarly pneumatically extends and retracts a central body, and uses a cam action to force legs outward by movement of the pipe crawler.
A common aspect of such prior art pipe crawlers is that they are made for crawling through either mostly empty pipes or pipes carrying low viscosity gases.
A different problem from that solved by such prior art pipe crawlers, arising from a different need than inspection and cleaning, is the need for systems for aiding rescue of trapped personnel in collapsed mines, buildings, and underground facilities (UGFs). Such collapsed structures may be caused by such events as natural disasters and terrorist actions.
The first requirement for such rescues is situational knowledge, which must be rapidly acquired without endangering additional personnel or those already trapped.
One approach for obtaining such necessary information is sending a robotically controlled and instrumented pipe crawler through a sewer pipe.
Such an unmanned robotically controlled system could infiltrate collapsed structures and provide lifesaving situational awareness of such important information as the existence and status of trapped personnel and at least some knowledge of the physical integrity of any remaining structure.
Sewer pipes are different from other, more open, pipes, and typical prior art pipe crawlers cannot crawl against the pressure from flowing sewer effluent.
Reasons that such prior art pipe crawlers cannot crawl against the pressure from flowing sewer effluent include an inability to attach to inside pipe walls with sufficient force, complicated by that the blunt, or bluff, overall shapes of such prior art pipe crawlers significantly increase the drag against them from effluent, or any liquid, flow.
The prior art for cleaning and inspecting pipes carrying high viscosity fluids, such as oil pipelines, uses so-called pipeline pigs, essentially slugs that fit closely inside a pipe and are moved along the pipe by the movement of the oil already moving through the pipe.
There is, therefore, a need for pipe crawlers that can crawl through sewer and other pipes against a flow of both low and high viscosity fluids.
There is an additional need for pipe crawlers that can climb vertical inclines and maneuver through pipe bends and around obstructions.